A center for definition and subtyping is proposed, with the following specific features: - longitudinal studies of educational and psychometric performance of a large sample of school children, to define and subtype dyslexia by outcome with careful control for the presence of attention deficit disorder (ADD) using tests already validated for separate effects of dyslexia and ADD; - a randomized experimental vs. control trial of remediation in the first and second grade, for children at high risk for dyslexia; - a full psychometric, neuropsychiatric, and regional cerebral blood flow investigation of a large sample of adult dyslexics whose childhood educational and psychometric performance is well-documented in archival records; and of their own children, permitting a two generation study where ascertainment is by affected parent; - electrophysiological event-related potential (ERP) measures, using paradigms already validated for separate effects of dyslexia and ADD.